Idle Functions using Advance

Give input on tuning as well as any tips and tricks you may have. Also feel free to share base mapping files for various engine types.

Idle Functions using Advance

Postby katana » Thu Jun 25, 2020 11:29 am

Hi All,
Just trimming some of the 'stock' map figures and trying to change the idle functions from using an IAV to advance control and have changed the 100 duty cycle for IAV to 20 for Advance max with PID of 10 and turned the 20x14 table off, PID turned on and advance control turned on but the map table doesn't change. Would I be correct in assuming this is totally ignored ? I'm not honestly clear on how timing advance for idle control actually works - does it just add whatever is set as a boost or is it variable?
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Re: Idle Functions using Advance

Postby Rob Stevens » Thu Jun 25, 2020 12:42 pm

The main map ignition settings are ignored when you have idle by ignition enabled, Depending on rpm and tps % settings in idle parameters.
You have a base idle map that gives the pid loop something to work on, don't get hung up on that just put something high in across the board and the pid will drag the rpm down slowly to your target based on temperature.
I think I mentioned elsewhere that you need to set the throttle blade artificially open to achieve good control. if your engine idles now with 12 deg the system won't respond well as it won't be able to increase rpm when cold.
Keep the 20x14 table on as it can be fine tuned later once you get to grips with how it works, there is really useful live info displayed in the base idle map so you can see what is going on.
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Re: Idle Functions using Advance

Postby katana » Thu Jun 25, 2020 3:15 pm

No - that doesn't make any sense to me! How are optimal timing figures arrived at if the main ign map is ignored?
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Re: Idle Functions using Advance

Postby stevieturbo » Thu Jun 25, 2020 5:15 pm

katana wrote:No - that doesn't make any sense to me! How are optimal timing figures arrived at if the main ign map is ignored?


Optimal for what ?

Timing at idle is a variable used to achieve a steady idle speed.
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Re: Idle Functions using Advance

Postby Rob Stevens » Fri Jun 26, 2020 2:00 am

Indeed, my road car will idle bang on 950 rpm , the control pid is constantly adjusting ignition to hold it there, it will even drive in 5th gear at idle, the pid ramps up to 26 deg (my max) to hold the target rpm, it works well. If that is what you call optimised, its constantly changing.
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Re: Idle Functions using Advance

Postby Alex DTA » Fri Jun 26, 2020 3:16 am

katana wrote:No - that doesn't make any sense to me! How are optimal timing figures arrived at if the main ign map is ignored?


The main map is ignored as it is fixed to RPM and load. Load is alway 0 at idle.
Idle ignition will also vary with temperature. So you have a map of RPM vs Temperature. If you are in an idle condition, the main map is ignored, and the idle map used instead.
This allows you to alter the timing on RPM, to control that, and also by temperature, as you will need more when it's cold.
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Re: Idle Functions using Advance

Postby rjwooll » Sat Jul 25, 2020 4:56 am

Why is the 20x14 Base Idle Advance table needed when ignition advance is the system adjusted variable in controlling target idle speed? My table just contains zeros without any apparent ill effects.
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Re: Idle Functions using Advance

Postby stevieturbo » Sat Jul 25, 2020 5:46 am

rjwooll wrote:Why is the 20x14 Base Idle Advance table needed when ignition advance is the system adjusted variable in controlling target idle speed? My table just contains zeros without any apparent ill effects.


It still needs a lookup table or can benefit from it, and you also have the option of open loop via the table.
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Re: Idle Functions using Advance

Postby rjwooll » Sat Jul 25, 2020 9:48 am

Thanks stevieturbo!

Thinking about it I'll populate the table with 10 degrees advance (close to normal for my engine) then there will be less delay before the PID adjustment kicks in.

The real time PID advance is shown next to the table; is the PWM% related to this, or does it only apply to idle air control valves? You can set enrichment to different PWM% values so I was wondering if this applies on an ignition advance setup.
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Re: Idle Functions using Advance

Postby Rob Stevens » Sun Jul 26, 2020 2:16 am

Hi, I think I have mentioned before that you throttle is closed too much as you are seeing 10 deg. open it a bit more to target 4 deg at idle, the idle control will work much better.
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